Currently available, non-culture based diagnostic tests for aspergillosis detect antigens circulating in blood. These tests, which detect β-1,3 glucan (GL) and galactomannan (GM), have variable performance characteristics and require relatively sophisticated and expensive laboratory resources to perform. The sophistication required for laboratory testing and the need for blood draw limit the application of currently available assays such that screening can be performed only infrequently and require health care facilities for phlebotomy and sample processing.
Development of an easy-to-use “point of care” (POC) assay would allow for frequent screening during the period in which a patient is at highest risk for an infection, especially after discharge from a health care facility. Lateral flow devices (LFD), also known as immunochromatographic strip tests, are a common POC testing method. LFDs reduce time spent waiting for test results (from hours to minutes), require less training for operators (thereby enabling user interpretation), and are less expensive both to manufacture and to use.
Fungi, as a group, are polysaccharide-rich organisms, which explains the relative success in the development of antigen-based assays for fungi. Some of these antigens are concentrated in urine. This characteristic, however, has been exploited for developing diagnostics for relatively rare endemic mycoses (e.g. coccidioidomycosis) only.